Kepler's Laws of planetary motion

[Erenjaeger]

Whose observations did Kepler use to prove that planets do in fact orbit in ellipses ?? Was it Tycho's observations?
Thanks.

 

[russ_watters]

Yes:
https://en.wikipedia.org/wiki/Kepler's_laws_of_planetary_motion#History

 

[sophiecentaur]

Tycho's observations

You really have to hand it to those early astronomers. Everything was measured using the naked eye and some very crude instruments. No Go-To telescopes available in those days. I guess the only thing on their side would have been No Light Pollution. (Put that candle out!)
Respect.

 

[phyzguy]

I don't think I would use the word "crude" to describe Tycho's Great Equatorial Armillary that he used to gather the observations that Kepler used. See the attached drawing. It was 3 meters in diameter and accurate to approximately 1 minute of arc. Of course we can do much better today, but for the time it was a very well designed and impressive instrument.

 

[sophiecentaur]

I don't think I would use the word "crude" to describe Tycho's Great Equatorial Armillary that he used to gather the observations that Kepler used. See the attached drawing. It was 3 meters in diameter and accurate to approximately 1 minute of arc. Of course we can do much better today, but for the time it was a very well designed and impressive instrument.

The word "crude" was comparative and not intended to offend anyone. I wouldn't mind betting that Keppler himself would have used the word if he could see what we use now.
One minute of arc is, in some respects, a barn door. The accuracy of clocks (time is as important as angle) was not good and I would reckon that accuracy of measuring long baselines would also not be very special.
No.They did a great job with what they had to hand.